Ionic inverse vulcanized polymer cross-linked bio-based Eucommia ulmoides gum with reprocessibility, shape memory and low-frequency sound absorption capability

Imidazolium-based ionic sulfur-rich polymer with bromonium ion (SBIM) was synthesized via the vulcanization polymerization of sulfur and ionic diene monomer (VBIM) for the thermally cross-linking of EUG, to generate the modified EUG (EUG-SBIM-xs) with ionic bonds and polysulfide bonds. The CN bonds transalkylation exchange and polysulfide bonds rearrangement of SBIM endowed the EUG-SBIM-xs with good thermally induced reprocessibility. Furthermore, the cross-linked EUG-SBIM-11.5 could completely dissolve in triphenylphosphine solution (in chloroform) via breaking the polysulfide bonds. The existence of imidazolium endowed the EUG-SBIM-xs with damping performance at around 60 °C. In addition, the thermally stimulated shape memory transition process was observed. Finally, the sound absorption properties were also investigated, and the EUG-SBIM-xs displayed high sound absorption coefficient in low-frequency.